DLA_PORPVGRW (3) Linux Manual Page

dla_porpvgrw.f –

Synopsis

Functions/Subroutines

DOUBLE PRECISION function dla_porpvgrw (UPLO, NCOLS, A, LDA, AF, LDAF, WORK)
DLA_PORPVGRW computes the reciprocal pivot growth factor norm(A)/norm(U) for a symmetric or Hermitian positive-definite matrix.

Function/Subroutine Documentation

DOUBLE PRECISION function dla_porpvgrw (character*1UPLO, integerNCOLS, double precision, dimension( lda, * )A, integerLDA, double precision, dimension( ldaf, * )AF, integerLDAF, double precision, dimension( * )WORK)

DLA_PORPVGRW computes the reciprocal pivot growth factor norm(A)/norm(U) for a symmetric or Hermitian positive-definite matrix.

Purpose:

 DLA_PORPVGRW computes the reciprocal pivot growth factor

 norm(A)/norm(U). The "max absolute element" norm is used. If this is

 much less than 1, the stability of the LU factorization of the

 (equilibrated) matrix A could be poor. This also means that the

 solution X, estimated condition numbers, and error bounds could be

 unreliable.

 

Parameters:

UPLO

 UPLO is CHARACTER*1

 = ‘U’: Upper triangle of A is stored;

 = ‘L’: Lower triangle of A is stored.

NCOLS

 NCOLS is INTEGER

 The number of columns of the matrix A. NCOLS >= 0.

A

 A is DOUBLE PRECISION array, dimension (LDA,N)

 On entry, the N-by-N matrix A.

LDA

 LDA is INTEGER

 The leading dimension of the array A. LDA >= max(1,N).

AF

 AF is DOUBLE PRECISION array, dimension (LDAF,N)

 The triangular factor U or L from the Cholesky factorization

 A = U**T*U or A = L*L**T, as computed by DPOTRF.

LDAF

 LDAF is INTEGER

 The leading dimension of the array AF. LDAF >= max(1,N).

WORK

 WORK is DOUBLE PRECISION array, dimension (2*N)

 

Author:

Univ. of Tennessee

Univ. of California Berkeley

Univ. of Colorado Denver

NAG Ltd.

Date:

September 2012

Definition at line 106 of file dla_porpvgrw.f.

Author

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